Modification of TA15 alloy surface by high-pulse-frequency laser cleaning

Abstract

The original morphology of the oxide layer and the surface of the titanium alloy has a significant impact on manufacturing and processing. The laser cleaning pulse frequency amplitude affects the single pulse energy. It will affect the original morphology of the surface and the compositional changes of the laser-generated oxide layer. This work aims to study the effect of pulse frequency on the surface morphology and the composition of laser-generated oxide layer of the TA15 alloy surface in laser cleaning. With normal pulse frequency (70 kHz), the surface roughness increased to micrometer order. The striation morphology was formed, accompanied by melting. With high pulse frequency (700 kHz), the surface roughness (Ra) decreased to submicrometer order. The striation morphology and the melting phenomenon weakened and disappeared. The change in pulse frequency results in different chemical bonds on the surface. With normal pulse frequency, the oxide layer forming on the surface was mainly composed of TiO2 and a small amount of TiO. With high pulse frequency, the oxide layer forming on the surface was mainly composed of TiO. After laser cleaning, the self-corrosion current of the sample decreased by orders of magnitude compared with that of untreated samples. The corrosion resistance increased as the pulse frequency increased. The self-corrosion potential increased with an increase in the TiO amount.